PROBLEM TO BE SOLVED: To provide a mobile vehicle capable of deciding whether or not the direction of travel of a running vehicle body is substantially identical to a target direction.SOLUTION: A riding rice transplanter comprises: a running vehicle body 2 having front wheels 10 and rear wheels 11 for running on a farm field a handle 34 for operating the running direction of the running vehicle body 2 a planting device 52 disposed on the back side of the running vehicle body for performing a planting operation in the farm field a plurality of left-forward side ultrasonic wave send-receive sensors 110La and left-backward side ultrasonic wave send-receive sensors 110Lb or the like that are arranged at different positions of the running vehicle body and detect information on the distance to a levee of the farm field and a control circuit 400 for deciding it on the basis of the information on the distance to be detected by the left-forward side ultrasonic wave send-receive sensor 110La, the left-backward side ultrasonic wave sens-receive sensor 110Lb or the like, whether or not the direction of the forward and backward directions of the running vehicle body are substantially parallel to the levee.SELECTED DRAWING: Figure 3
